1. Field
The present invention relates to the fabrication of integrated circuits, particularly to methods and apparatuses for pre-cleaning a substrate surface.
2. Description of the Related Art
Fabrication of integrated circuits often can involve formation of one or more material layers on a substrate surface. These material layers can include, for example, mono-crystalline, polycrystalline, and/or amorphous material layers. Formation of the material layers can be achieved using various thin film deposition techniques, including various physical (e.g., physical sputtering) and/or chemical (e.g., chemical vapor deposition, atomic layer deposition, and/or epitaxial deposition) deposition techniques. For example, mono-crystalline material formation on a substrate surface can be performed using an epitaxial deposition process, such as for formation of mono-crystalline semiconductor materials (e.g., mono-crystalline silicon).
The presence of an intervening material (e.g., a native oxide layer, such as an oxide material layer comprising silicon and germanium on a silicon-germanium substrate) on the substrate surface may interfere with formation of a desired material layer over that substrate surface. For example, the intervening material may cause introduction of an increased number of defects in the structure of the desired material layer and/or may adversely affect an electrical performance of the desired material layer. In some embodiments, an intervening material such as a native oxide material may form on a substrate surface due to exposure of the substrate to oxygen during the integrated circuit fabrication process (e.g., exposure to ambient air during transfer of the substrate between fabrication systems, and/or to residual oxidizing agents within fabrication systems).
Accordingly, there is a continuing need for processes for forming high quality layers on a substrate surface.